1. Field of the Invention
This invention relates to a valve guide member as one of component members of an internal combustion engine, which is formed of an Fe-based sintered alloy having excellent wear and abrasion resistance.
2. Prior Art
It is well known that conventionally a great many Fe-based sintered alloys have been used as valve guide members in internal combustion engines.
In recent years, internal combustion engines have made remarkable progress in output and speed characteristics so that they exhibit higher output and higher speed performance, and accordingly component members constituting the internal combustion engines are used under severer conditions. These component members include valve guide members for guiding inlet valves and exhaust valves of the engine which are slidably fitted in bores formed in the valve guide members for reciprocating motion. The valve guide members undergo heavy wear and abrasion due to sliding contact with the valves (valve stems). Therefore, further improved wear and abrasion resistance is required of the valve guide members. In actuality, however, the conventional valve guide members formed of Fe-based sintered alloys do not exhibit satisfactory wear and abrasion resistance to cope with the wear and abrasion due to the sliding contact.